The present invention relates to a solenoid valve control apparatus that removes foreign matter or object formed by adhesion at a valve open/close portion, by performing a reciprocating movement of a plunger through the application of a rectangular-wave current of low frequency in place of a high-frequency driving current of a normal control.
In a case of a normally high two-way linear solenoid valve that outputs a high pressure with the valve closed when a solenoid current applied to a solenoid coil is 0 (zero), the foreign matter is apt to adhere to valve open/close portion between the plunger (or a valve body integrally formed with the plunger) and a valve seat inside the valve. The reason why the foreign matter is apt to adhere to valve open/close portion is that the solenoid current applied to the solenoid coil is the high-frequency driving current and oil pulsates at the valve open/close portion then the oil accumulates or builds up there with the valve closed when the solenoid current is 0 (zero).
For this problem, in Japanese Patent Provisional Publication No. 2005-54970 (hereinafter is referred to as “JP2005-54970”), a solenoid valve control apparatus that pulls away the foreign matter that adheres to or becomes trapped at the valve open/close portion has been proposed. More specifically, in order to efficiently remove the foreign matter that adheres to the valve open/close portion of the linear solenoid valve, as the solenoid current applied to the solenoid coil, a rectangular-wave current by which maximum and minimum values of a current command value are alternately repeated is applied, and the reciprocating action or movement of the plunger is performed, then the foreign matter is removed.